Blow Molding Polymers with Improved Cycle Time, Processability, and Surface Quality

ABSTRACT

Ethylene-based polymers having a density of 0.952 to 0.965 g/cm3, a high load melt index (HLMI) from 5 to 25 g/10 min, a weight-average molecular weight from 275,000 to 450,000 g/mol, a number-average molecular weight from 15,000 to 40,000 g/mol, a viscosity at HLMI from 1400 to 4000 Pa-sec, and a tangent delta at 0.1 sec−1 from 0.65 to 0.98 degrees. These polymers have the processability of chromium-based resins, but with improved stress crack resistance, and can be used in large-part blow molding applications.

BACKGROUND OF THE INVENTION

Polyolefins such as high density polyethylene (HDPE) homopolymer andcopolymer and linear low density polyethylene (LLDPE) copolymer can beproduced using various combinations of catalyst systems andpolymerization processes. Chromium-based catalyst systems can, forexample, produce olefin polymers having good extrusion processabilityand polymer melt strength, typically due to their broad molecular weightdistribution (MWD).

In some end-use applications, it can be beneficial to have theprocessability, cycle time, and melt strength similar to that of anolefin polymer produced from a chromium-based catalyst system, as wellas improvements in one or more of toughness, impact strength, andenvironmental stress crack resistance (ESCR)—and preferably atequivalent or higher polymer densities. Accordingly, it is to these endsthat the present invention is generally directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

The present invention generally relates to ethylene polymers (e.g.,ethylene/α-olefin copolymers) characterized by a density in a range fromabout 0.952 to about 0.965 g/cm³, a high load melt index (HLMI) in arange from about 5 to about 25 g/10 min, a weight-average molecularweight (Mw) in a range from about 275,000 to about 450,000 g/mol, anumber-average molecular weight (Mn) in a range from about 15,000 toabout 40,000 g/mol, a viscosity at HLMI (eta A HLMI or η @ HLMI) in arange from about 1400 to about 4000 Pa-sec, and a tan δ (tan d ortangent delta) at 0.1 sec⁻¹ in a range from about 0.65 to about 0.98degrees. Also disclosed and encompassed herein are ethylene polymershaving a density in a range from about 0.952 to about 0.965 g/cm³, aHLMI in a range from about 5 to about 25 g/10 min, a Mw in a range fromabout 275,000 to about 450,000 g/mol, a Mn in a range from about 15,000to about 28,000 g/mol, and a η @ HLMI in a range from about 1400 toabout 4000 Pa-sec. The ethylene polymers described herein can be used toproduce various articles of manufacture, such as blow molded products.

Another aspect of this invention is directed to a dual catalyst system,and in this aspect, the dual catalyst system can comprise catalystcomponent I comprising an unbridged metallocene compound, catalystcomponent II comprising a bridged metallocene compound, an activator,and optionally, a co-catalyst. In yet another aspect, an olefinpolymerization process is provided, and in this aspect, the process cancomprising contacting any catalyst composition disclosed herein with anolefin monomer and an optional olefin comonomer in a polymerizationreactor system under polymerization conditions to produce an olefinpolymer. For instance, the olefin monomer can be ethylene, and theolefin comonomer can be 1-butene, 1-hexene, 1-octene, or a mixturethereof.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects andembodiments may be directed to various feature combinations andsub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE FIGURE

FIG. 1 presents a plot of the molecular weight distributions of thepolymers of Examples 1-4.

FIG. 2 presents a plot of the molecular weight distributions of thepolymers of Examples 5-8.

FIG. 3 presents a plot of the molecular weight distributions of thepolymers of Examples 1, 5, and 9.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IMPACCompendium of Chemical Terminology, 2nd Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features can beenvisioned. For each and every aspect and/or feature disclosed herein,all combinations that do not detrimentally affect the designs,compositions, and/or methods described herein are contemplated with orwithout explicit description of the particular combination.Additionally, unless explicitly recited otherwise, any aspect and/orfeature disclosed herein can be combined to describe inventive featuresconsistent with the present disclosure.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodsalso can “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a catalyst compositionconsistent with aspects of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; catalyst component I, catalyst component II, an activator, and aco-catalyst.

The terms “a,” “an,” “the,” etc., are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a metallocenecompound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or metallocene compound, respectively,unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound disclosed herein, the general structure orname presented is also intended to encompass all structural isomers,conformational isomers, and stereoisomers that can arise from aparticular set of substituents, unless indicated otherwise. Thus, ageneral reference to a compound includes all structural isomers unlessexplicitly indicated otherwise; e.g., a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane, while ageneral reference to a butyl group includes an n-butyl group, asec-butyl group, an iso-butyl group, and a tert-butyl group.Additionally, the reference to a general structure or name encompassesall enantiomers, diastereomers, and other optical isomers whether inenantiomeric or racemic forms, as well as mixtures of stereoisomers, asthe context permits or requires. For any particular formula or name thatis presented, any general formula or name presented also encompasses allconformational isomers, regioisomers, and stereoisomers that can arisefrom a particular set of substituents.

The term “substituted” when used to describe a group, for example, whenreferring to a substituted analog of a particular group, is intended todescribe any non-hydrogen moiety that formally replaces a hydrogen inthat group, and is intended to be non-limiting. A group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Unless otherwise specified, “substituted” is intended to be non-limitingand include inorganic substituents or organic substituents as understoodby one of ordinary skill in the art.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen. Otheridentifiers can be utilized to indicate the presence of particulargroups in the hydrocarbon (e.g., halogenated hydrocarbon indicates thepresence of one or more halogen atoms replacing an equivalent number ofhydrogen atoms in the hydrocarbon). The term “hydrocarbyl group” is usedherein in accordance with the definition specified by IUPAC: a univalentgroup formed by removing a hydrogen atom from a hydrocarbon (that is, agroup containing only carbon and hydrogen). Non-limiting examples ofhydrocarbyl groups include alkyl, alkenyl, aryl, and aralkyl groups,amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and the like, as well as alloysand blends thereof. The term “polymer” also includes impact, block,graft, random, and alternating copolymers. A copolymer is derived froman olefin monomer and one olefin comonomer, while a terpolymer isderived from an olefin monomer and two olefin comonomers. Accordingly,“polymer” encompasses copolymers and terpolymers derived from any olefinmonomer and comonomer(s) disclosed herein. Similarly, the scope of theterm “polymerization” includes homopolymerization, copolymerization, andterpolymerization. Therefore, an ethylene polymer includes ethylenehomopolymers, ethylene copolymers (e.g., ethylene/α-olefin copolymers),ethylene terpolymers, and the like, as well as blends or mixturesthereof. Thus, an ethylene polymer encompasses polymers often referredto in the art as LLDPE (linear low density polyethylene) and HDPE (highdensity polyethylene). As an example, an olefin copolymer, such as anethylene copolymer, can be derived from ethylene and a comonomer, suchas 1-butene, 1-hexene, or 1-octene. If the monomer and comonomer wereethylene and 1-hexene, respectively, the resulting polymer can becategorized an as ethylene/1-hexene copolymer. The term “polymer” alsoincludes all possible geometrical configurations, unless statedotherwise, and such configurations can include isotactic, syndiotactic,and random symmetries. Moreover, unless stated otherwise, the term“polymer” also is meant to include all molecular weight polymers, and isinclusive of lower molecular weight polymers.

The term “co-catalyst” is used generally herein to refer to compoundssuch as aluminoxane compounds, organoboron or organoborate compounds,ionizing ionic compounds, organoaluminum compounds, organozinccompounds, organomagnesium compounds, organolithium compounds, and thelike, that can constitute one component of a catalyst composition, whenused, for example, in addition to an activator-support. The term“co-catalyst” is used regardless of the actual function of the compoundor any chemical mechanism by which the compound may operate.

The terms “chemically-treated solid oxide,” “treated solid oxidecompound,” and the like, are used herein to indicate a solid, inorganicoxide of relatively high porosity, which can exhibit Lewis acidic orBronsted acidic behavior, and which has been treated with anelectron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide can comprise a calcined contact product of at least onesolid oxide with at least one electron-withdrawing anion sourcecompound. Typically, the chemically-treated solid oxide comprises atleast one acidic solid oxide compound. The “activator-support” of thepresent invention can be a chemically-treated solid oxide. The terms“support” and “activator-support” are not used to imply these componentsare inert, and such components should not be construed as an inertcomponent of the catalyst composition. The term “activator,” as usedherein, refers generally to a substance that is capable of converting ametallocene component into a catalyst that can polymerize olefins, orconverting a contact product of a metallocene component and a componentthat provides an activatable ligand (e.g., an alkyl, a hydride) to themetallocene, when the metallocene compound does not already comprisesuch a ligand, into a catalyst that can polymerize olefins. This term isused regardless of the actual activating mechanism. Illustrativeactivators include activator-supports, aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and the like.Aluminoxanes, organoboron or organoborate compounds, and ionizing ioniccompounds generally are referred to as activators if used in a catalystcomposition in which an activator-support is not present. If thecatalyst composition contains an activator-support, then thealuminoxane, organoboron or organoborate, and ionizing ionic materialsare typically referred to as co-catalysts.

The term “metallocene” as used herein describes compounds comprising atleast one η³ to η⁵-cycloalkadienyl-type moiety, wherein η³ toη⁵-cycloalkadienyl moieties include cyclopentadienyl ligands, indenylligands, fluorenyl ligands, and the like, including partially saturatedor substituted derivatives or analogs of any of these. Possiblesubstituents on these ligands can include H, therefore this inventioncomprises ligands such as tetrahydroindenyl, tetrahydrofluorenyl,octahydrofluorenyl, partially saturated indenyl, partially saturatedfluorenyl, substituted partially saturated indenyl, substitutedpartially saturated fluorenyl, and the like. In some contexts, themetallocene is referred to simply as the “catalyst,” in much the sameway the term “co-catalyst” is used herein to refer to, for example, anorganoaluminum compound.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the co-catalyst, catalystcomponent I, catalyst component II, or the activator (e.g.,activator-support), after combining these components. Therefore, theterms “catalyst composition,” “catalyst mixture,” “catalyst system,” andthe like, encompass the initial starting components of the composition,as well as whatever product(s) may result from contacting these initialstarting components, and this is inclusive of both heterogeneous andhomogenous catalyst systems or compositions. The terms “catalystcomposition,” “catalyst mixture,” “catalyst system,” and the like, canbe used interchangeably throughout this disclosure.

The term “contact product” is used herein to describe compositionswherein the components are contacted together in any order, in anymanner, and for any length of time, unless otherwise specified. Forexample, the components can be contacted by blending or mixing. Further,contacting of any component can occur in the presence or absence of anyother component of the compositions described herein. Combiningadditional materials or components can be done by any suitable method.Further, the term “contact product” includes mixtures, blends,solutions, slurries, reaction products, and the like, or combinationsthereof. Although “contact product” can include reaction products, it isnot required for the respective components to react with one another.Similarly, the term “contacting” is used herein to refer to materialswhich can be blended, mixed, slurried, dissolved, reacted, treated, orotherwise combined in some other manner.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices, and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

Several types of ranges are disclosed in the present invention. When arange of any type is disclosed or claimed, the intent is to disclose orclaim individually each possible number that such a range couldreasonably encompass, including end points of the range as well as anysub-ranges and combinations of sub-ranges encompassed therein. Forexample, When a chemical moiety having a certain number of carbon atomsis disclosed or claimed, the intent is to disclose or claim individuallyevery possible number that such a range could encompass, consistent withthe disclosure herein. For example, the disclosure that a moiety is a C₁to C₁₈ hydrocarbyl group, or in alternative language, a hydrocarbylgroup having from 1 to 18 carbon atoms, as used herein, refers to amoiety that can have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, or 18 carbon atoms, as well as any range between these twonumbers (for example, a C₁ to C₈ hydrocarbyl group), and also includingany combination of ranges between these two numbers (for example, a C₂to C₄ and a C₁₂ to C₁₆ hydrocarbyl group).

Similarly, another representative example follows for the ratio of Mw/Mnof an ethylene polymer consistent with aspects of this invention. By adisclosure that the ratio of Mw/Mn can be in a range from about 10 toabout 20, the intent is to recite that the ratio of Mw/Mn can be anyratio in the range and, for example, can be equal to about 10, about 11,about 12, about 13, about 14, about 15, about 16, about 17, about 18,about 19, or about 20. Additionally, the ratio of Mw/Mn can be withinany range from about 10 to about 20 (for example, from about 10 to about18), and this also includes any combination of ranges between about 10and about 20 (for example, the Mw/Mn ratio can be in a range from about10 to about 14, or from about 16 to about 19). Further, in allinstances, where “about” a particular value is disclosed, then thatvalue itself is disclosed. Thus, the disclosure that the ratio of Mw/Mncan be from about 10 to about 20 also discloses a ratio of Mw/Mn from 10to 20 (for example, from 10 to 18), and this also includes anycombination of ranges between 10 and 2.0 (for example, the Mw/Mn ratiocan be in a range from 10 to 14, or from 16 to 19). Likewise, all otherranges disclosed herein should be interpreted in a manner similar tothese examples.

The term “about” means that amounts, sizes, formulations, parameters,and other quantities and characteristics are not and need not be exact,but can be approximate and/or larger or smaller, as desired, reflectingtolerances, conversion factors, rounding off, measurement errors, andthe like, and other factors known to those of skill in the art. Ingeneral, an amount, size, formulation, parameter or other quantity orcharacteristic is “about” or “approximate” whether or not expresslystated to be such. The term “about” also encompasses amounts that differdue to different equilibrium conditions for a composition resulting froma particular initial mixture. Whether or not modified by the term“about,” the claims include equivalents to the quantities. The term“about” can mean within 10% of the reported numerical value, preferablywithin 5% of the reported numerical value.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to dual metallocene catalystsystems, methods for using the catalyst systems to polymerize olefins,the polymer resins produced using such catalyst systems, and articlesproduced using these polymer resins. In particular, the presentinvention relates to ethylene-based polymers having excellent ESCR andstrength properties, but with improved processability and reduced cycletimes in blow molding applications. Articles produced from theseethylene-based polymers have interior and exterior surfaces that aresubstantially free of defects.

Conventional chromium-based resins for blow molding applicationsgenerally have a broad MWD, acceptable die/weight swell, high meltstrength, and overall excellent processability on a wide range of blowmolding machinery. Notwithstanding these benefits, improvements intoughness, impact strength, and ESCR are desired. Ethylene-basedpolymers described herein, in certain aspects, can provide suchimprovements along with the ease of processing typically associated withconventional chromium-based resins (e.g., acceptable die/weight swell,high melt strength, good processability, etc.). For instance, theethylene polymers described herein have significantly better ESCRproperties than conventional chromium-based resins, and unexpectedly,can be converted into blow molded products at cycle times that are lessthan that of conventional chromium-based resins. Beneficially, lowercycle times can translate into higher production rates (more blow moldedparts per hour), resulting in better cost efficiency.

Advantageously, the ethylene polymers disclosed herein also provideimprovements over other metallocene-based blow molding resins. Forexample, in the blow molding production of large parts such as outdoorstorage products (e.g., panels for walls of an outdoor shed) and outdoorplay equipment (e.g., kayaks, bases for basketball goals), conventionalmetallocene-based blow molding resins produce parts with goodstrength/toughness, but with several drawbacks. First, there isexcessive die/weight swell, resulting in overflowing of the mold.Second, extrusion processability is negatively impacted, with highbackpressure, reduced extrusion output, and longer cycle times. Lastly,the surface appearance is often unacceptable, with surface streaking,surface roughness, or other surface defects, which can render the blowmolded part unfit for sale.

It was unexpectedly found that the combination of polymer properties ofthe ethylene polymers disclosed herein results in improvements over theconventional chromium-based and metallocene-based blow molding resins,in particular, for large blow molded parts. The molecular weightproperties of the resin—e.g., as reflected by Mw and HLMI—must besufficiently high to result in a melt strength suitable for large blowmolded parts, with much more stringent requirements than small blowmolded products, such as milk bottles. However, the melt viscosity athigh shear rates e.g., as reflected by the η @ HLMI—cannot be too high,or extrusion processability (high backpressure and melt temperature) andcycle time will be negatively impacted. Further, and not wishing to bebound by the following theory, it is believed that the combined polymerproperties of HLMI, Mw, Mn, η @ HLMI, and/or tan δ may result in thedesired die swell and excellent surface aesthetics of the blow moldedparts.

Ethylene Polymers

Generally, the polymers disclosed herein are ethylene-based polymers, orethylene polymers, encompassing homopolymers of ethylene as well ascopolymers, terpolymers, etc., of ethylene and at least one olefincomonomer. Comonomers that can be copolymerized with ethylene often canhave from 3 to 20 carbon atoms in their molecular chain. For example,typical comonomers can include, but are not limited to, propylene,1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and the like, orcombinations thereof. In an aspect, the olefin comonomer can comprise aC₃-C₁₈ olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₄-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀α-olefin; alternatively, the olefin comonomer can comprise a C₄-C₁₀α-olefin; alternatively, the olefin comonomer can comprise 1-butene,1-hexene, 1-octene, or any combination thereof; or alternatively, thecomonomer can comprise 1-hexene. Typically, the amount of the comonomer,based on the total weight of monomer (ethylene) and co monomer, can bein a range from about 0.01 to about 20 wt. %, from about 0.1 to about 10wt. %, from about 0.5 to about 15 wt. %, from about 0.5 to about 8 wt.%, or from about 1 to about 15 wt. %.

In one aspect, the ethylene polymer of this invention can comprise anethylene/α-olefin copolymer, while in another aspect, the ethylenepolymer can comprise an ethylene homopolymer, and in yet another aspect,the ethylene polymer of this invention can comprise an ethylene/α-olefincopolymer and an ethylene homopolymer. For example, the ethylene polymercan comprise an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, an ethylene/1-octene copolymer, an ethylene homopolymer, orany combination thereof; alternatively, an ethylene/1-butene copolymer,an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or anycombination thereof; or alternatively, an ethylene/1-hexene copolymer.

An illustrative and non-limiting example of an ethylene polymer (e.g.,comprising an ethylene copolymer) consistent with the present inventioncan have a density in a range from about 0.952 to about 0.965 g/cm³, ahigh load melt index (HLMI) in a range from about 5 to about 25 g/10min, a weight-average molecular weight (Mw) in a range from about275,000 to about 450,000 gr/mol, a number-average molecular weight (Mn)in a range from about 15,000 to about 40,000 g/mol, a viscosity at HLMI(eta @ HLMI or η @ HLMI) in a range from about 1400 to about 4000Pa-sec, and a tan δ (tan d or tangent delta) at 0.1 sec⁻¹ in a rangefrom about 0.65 to about 0.98 degrees. Another illustrative andnon-limiting example of an ethylene polymer consistent with the presentinvention can have a density in a density in a range from about 0.952 toabout 0.965 g/cm³, a HLMI in a range from about 5 to about 25 g/10 min,a Mw in a range from about 275,000 to about 450,000 g/mol, a Mn in arange from about 15,000 to about 28,000 g/mol, and a η @ HLMI in a rangefrom about 1400 to about 4000 Pa-sec. These illustrative andnon-limiting examples of ethylene polymers consistent with the presentinvention also can have any of the polymer properties listed below andin any combination, unless indicated otherwise.

The densities of ethylene-based polymers disclosed herein often aregreater than or equal to about 0.95 g/cm³, for example, greater than orequal to about 0.952 g/cm³, or greater than or equal to about 0.9542/cm³. Yet, in particular aspects, the density can be in a range fromabout 0.952 to about 0.962 g/cm³, from about 0.952 to about 0.96g/cm^(s), from about 0.954 to about 0.965 g/cm³, from about 0.954 toabout 0.962 g/cm³, or from about 0.954 to about 0.96 g/cm³.

Ethylene polymers described herein often can have a melt index (MI) ofless than or equal to about 1 g/10 min, less than or equal to about 0.7g/10 min, or less than or equal to about 0.6 g/10 min. In furtheraspects, ethylene polymers described herein can have a melt index (MI)of less than or equal to about 0.4 g/10 min, less than or equal to about0.3 g/10 min, less than or equal to about 0.2 g/10 min, or less than orequal to about 0.1 g/10 min.

While not being limited thereto, the ethylene polymer can have a highload melt index (HLMI) in a range from about 5 to about 25 g/10 min;alternatively, from about 5 to about 20 g/10 min; alternatively, fromabout 5 to about 18 g/10 min; alternatively, from about 6 to about 18g/10 min; alternatively, from about 6 to about 16 g/10 min; oralternatively, from about 7 to about 15 g/10 min.

In an aspect, ethylene polymers described herein can have a ratio ofMw/Mn, or the polydispersity index, in a range from about 7 to about 20,from about 7 to about 18, from about 8 to about 20, from about 8 toabout 18, from about 10 to about 20, from about 10 to about 18, or fromabout 11 to about 17. Additionally or alternatively, the ethylenepolymer can have a ratio of Mz/Mw in a range from about 4 to about 9,from about 4.5 to about 8, from about 4.5 to about 7.5, or from about 5to about 7.

In an aspect, ethylene polymers described herein can have aweight-average molecular weight (Mw) in a range from about 275,000 toabout 425,000, from about 275,000 to about 400,000, from about 300,000to about 450,000, from about 300,000 to about 425,000, from about300,000 to about 400,000, from about 325,000 to about 450,000, fromabout 325,000 to about 425,000, or from about 325,000 to about 400,000g/mol. Additionally or alternatively, the ethylene polymer can have anumber-average molecular weight (Mn) in a range from about 15,000 toabout 40,000, from about 15,000 to about 35,000, from about 15,000 toabout 28,000, from about 17,000 to about 40,000, from about 17,000 toabout 35,000, or from about 17,000 to about 27,000 g/mol. Additionallyor alternatively, the ethylene polymer can have a z-average molecularweight (Mz) in a range from about 1,500,000 to about 3,000,000, fromabout 1,750,000 to about 3,000,000, from about 1,500,000 to about2,750,000, from about 1,750,000 to about 2,750,000, or from about1,850,000 to about 2,750,000 g/mol. Additionally or alternatively, theethylene polymer can have a peak molecular weight (Mp) in a range fromabout 45,000 to about 85,000, from about 45,000 to about 65,000, fromabout 50,000 to about 80,000, or from about 50,000 to about 62,000g/mol.

Ethylene polymers consistent with certain aspects of the invention oftencan have a bimodal molecular weight distribution (as determined usinggel permeation chromatography (GPC) or other related analyticaltechnique). Often, in a bimodal molecular weight distribution, there isa valley between the peaks, and the peaks can be separated ordeconvoluted. Typically, a bimodal molecular weight distribution can becharacterized as having an identifiable high molecular weight component(or distribution) and an identifiable low molecular weight component (ordistribution). Illustrative unimodal MWD curves and bimodal MWD curvesare shown in U.S. Pat. No. 8,383,754, incorporated herein by referencein its entirety.

While not limited thereto, ethylene polymers described herein can have azero-shear viscosity at 190° C. of greater than or equal to about 5×10⁵,greater than or equal to about 7.5×10⁵, greater than or equal to about1×10⁶, or in a range from about 1×10⁶ to about 1×10⁷ Pa-sec.Additionally or alternatively, these ethylene polymers can have a CY-aparameter of from about 0.1 to about 0.45, from about 0.15 to about 0.4,from about 0.18 to about 0.36, or from about 0.2 to about 0.35, and thelike. Additionally or alternatively, these ethylene polymers can becharacterized by a viscosity at HLMI (eta @ HLMI or η @ HLMI) at 190° C.in a range from about 1400 to about 4000 Pa-sec, and more often, in arange from about 1500 to about 4000, from about 1600 to about 4000, fromabout 1400 to about 3900, from about 1500 to about 3900, or from about1600 to about 3900 Pa-sec. Additionally or alternatively, these ethylenepolymers can have a viscosity at 100 sec⁻¹ (eta @ 100 or η @ 100) at190° C. in a range from about 1500 to about 3000, from about 1600 toabout 2800, from about 1700 to about 2700, from about 1650 to about2650, or from about 1750 to about 2500 Pa-sec. Additionally oralternatively, these ethylene polymers can have a ratio of 0.1/η @ 100(the viscosity at 0.1 sec⁻¹ divided by the viscosity at 100 sec⁻¹) in arange from about 50 to about 150, from about 60 to about 130, from about85 to about 130, or from about 90 to about 120. Additionally oralternatively, these ethylene polymers can have a tan δ (tan d ortangent delta) at 0.1 sec⁻¹ and 190° C. in a range from about 0.65 toabout 0.98 degrees, and more often, from about 0.7 to about 0.98degrees, from about 0.7 to about 0.95 degrees, from about 0.8 to about0.98 degrees, or from about 0.82 to about 0.97 degrees. Theserheological parameters are determined from viscosity data measured at190° C. and using the Marceau-Yasuda (CY) empirical model as describedherein.

Generally, ethylene polymers in aspects of the present invention areessentially linear or have very low levels of long chain branching, withtypically less than about 0.01 long chain branches (LCBs) per 1000 totalcarbon atoms—using the Janzen-Colby model—and often similar in LCBcontent to polymers shown, for example, in U.S. Pat. Nos. 7,517,939,8,114,946, and 8,383,754, which are incorporated herein by reference intheir entirety. In some aspects, the number of LCBs per 1000 totalcarbon atoms can be less than about 0.008, less than about 0.007, lessthan about 0.005, or less than about 0.003 LCBs per 1000 total carbonatoms.

Ethylene copolymers, for example, produced using the polymerizationprocesses and catalyst systems described herein can, in some aspects,have a reverse comonomer distribution, generally, the higher molecularweight components of the polymer have higher comonomer incorporationthan the lower molecular weight components. Typically, there isincreasing comonomer incorporation with increasing molecular weight. Inone aspect, the number of short chain branches (SCBs) per 1000 totalcarbon atoms of the polymer can be greater at Mw than at Mn. In anotheraspect, the number of SCBs per 1000 total carbon atoms of the polymercan be greater at Mz than at Mw. In yet another aspect, the number ofSCBs per 1000 total carbon atoms of the polymer can be greater at Mzthan at Mn.

Consistent with aspects of this disclosure, the ethylene polymers canhave an environmental stress crack resistance (ESCR) of at least 250hours. Moreover, in some aspects, the ethylene polymers described hereincan have an ESCR of at least 500 hours, at least 750 hours, at least1,000 hours, at least 1,500 hours, at least 1,750 hours, or at least2,000 hours, and often can range as high as 2,500 to 4,000 hours. TheESCR test is typically stopped after a certain number of hours isreached, and given the long duration of the test, the upper limit ofESCR (in hours) is generally not determined. ESCR testing and testresults disclosed herein are in accordance with ASTM D1693, condition B,10% igepal, which is a much more stringent test than ESCR testingconducted using a 100% igepal solution.

While not being limited thereto, the ethylene polymers described hereincan have an IVc (intrinsic viscosity determined by GPC) that typicallyfalls within a range from about 2.9 to about 3.7, from about 3 to about3.6, or from about 3.1 to about 3.5 dL/g. Additionally or alternatively,these ethylene polymers can have a ratio of Mn/IVc (Mn in kg/mol and IVcin dL/g) typically in a range from about 5.5 to about 12, from about 6to about 10, from about 5.5 to about 8.2, or from about 6 to about 8.

Aspects of this invention also are directed to the performance of theethylene polymer (e.g., an ethylene/1-hexene copolymer) onrepresentative blow molding equipment, as described herein below.Ethylene polymers described herein can have a cycle time from about 150to about 300, from about 150 to about 275, from about 160 to about 280,or from about 160 to about 260 seconds; unexpectedly, these polymers canhave cycle times less than that of comparable chromium-based resins.Additionally or alternatively, ethylene polymers described herein canhave a part weight in a range from about 1800 to about 2500, from about1800 to about 2200, from about 1800 to about 2100, from about 1850 toabout 2100, or from about 1850 to about 2050 grams. Additionally oralternatively, ethylene polymers described herein can have a layflat(top) in a range from about 9.3 to about 10.5, from about 9.5 to about10.5, or from about 9.6 to about 10.3 inches.

In an aspect, the ethylene polymer described herein can be a reactorproduct (e.g., a single reactor product), for example, not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics. As one of skill in the art wouldreadily recognize, physical blends of two different polymer resins canbe made, but this necessitates additional processing and complexity notrequired for a reactor product.

Moreover, the ethylene polymers can be produced with dual metallocenecatalyst systems containing zirconium and/or hafnium, discussed furtherbelow. Ziegler-Natta and chromium based catalysts systems are notrequired. Therefore, the ethylene polymer can contain no measurableamount of chromium or titanium (catalyst residue), i.e., less than 0.1ppm by weight. In some aspects, the ethylene polymer can contain,independently, less than 0.08 ppm, less than 0.05 ppm, or less than 0.03ppm, of chromium and titanium.

Articles and Products

Articles of manufacture can be formed from, and/or can comprise, theolefin polymers (e.g., ethylene polymers) of this invention and,accordingly, are encompassed herein. For example, articles which cancomprise the polymers of this invention can include, but are not limitedto, an agricultural film, an automobile part, a bottle, a container forchemicals, a drum, a fiber or fabric, a food packaging film orcontainer, a food service article, a fuel tank, a geomembrane, ahousehold container, a liner, a molded product, a medical device ormaterial, an outdoor storage product (e.g., panels for walls of anoutdoor shed), outdoor play equipment (e.g., kayaks, bases forbasketball goals), a pipe, a sheet or tape, a toy, or a traffic barrier,and the like. Various processes can be employed to form these articles.Non-limiting examples of these processes include injection molding, blowmolding, rotational molding, film extrusion, sheet extrusion, profileextrusion, thermoforming, and the like. Additionally, additives andmodifiers often are added to these polymers in order to providebeneficial polymer processing or end-use product attributes. Suchprocesses and materials are described in Modern Plastics Encyclopedia,Mid-November 1995 Issue, Vol. 72, No. 12; and Film ExtrusionManual—Process, Materials, Properties, TAPPI Press, 1992; thedisclosures of which are incorporated herein by reference in theirentirety. In some aspects of this invention, an article of manufacturecan comprise any of olefin polymers (or ethylene polymers) describedherein, and the article of manufacture can be or can comprise a blowmolded product.

Beneficially, the articles (e.g., blow molded articles) formed from orcomprising the disclosed ethylene polymers have excellent surfacequality or surface aesthetics. This can be quantified as described inthe examples that follow. Generally, articles (e.g., blow moldedarticles) contemplated herein can have less than 10 protrusions orsevere surface defects in the article, while in some aspects, less than5 or less than 2 protrusions or severe surface defects, and inparticular aspects, only 1 protrusion or severe surface defect, or zeroprotrusions or severe surface defects in the article.

Also contemplated herein is a method for forming or preparing an articleof manufacture comprising any polymer disclosed herein. For instance, amethod can comprise (i) contacting a catalyst composition with an olefinmonomer (e.g., ethylene) and an optional olefin comonomer underpolymerization conditions in a polymerization reactor system to producean olefin polymer (e.g., an ethylene polymer), wherein the catalystcomposition can comprise catalyst component I, catalyst component II, anactivator (e.g., an activator-support comprising a solid oxide treatedwith an electron-withdrawing anion), and an optional co-catalyst (e.g.,an organoaluminum compound); and (ii) forming an article of manufacturecomprising the olefin polymer (or ethylene polymer). The forming stepcan comprise blending, melt processing, extruding, molding (e.g., blowmolding), or thermoforming, and the like, including combinationsthereof. Any suitable additive can be combined with the polymer in themelt processing step (extrusion step), such as antioxidants, acidscavengers, antiblock additives, slip additives, colorants, fillers,processing aids, UV inhibitors, and the like, as well as combinationsthereof.

Catalyst Systems and Polymerization Processes

In accordance with aspects of the present invention, the olefin polymer(e.g., the ethylene polymer) can be produced using a dual catalystsystem. In these aspects, catalyst component I can comprise any suitableunbridged metallocene compound disclosed herein, and catalyst componentII can comprise any suitable bridged metallocene compound disclosedherein. The catalyst system also can comprise any suitable activator orany activator disclosed herein, and optionally, any suitable co-catalystor any co-catalyst disclosed herein.

Referring first to catalyst component I, which can comprise an unbridgedzirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group. In one aspect, catalyst component I can comprise anunbridged zirconium or hafnium based metallocene compound containing twocyclopentadienyl groups. In another aspect, catalyst component I cancomprise an unbridged zirconium or hafnium based metallocene compoundcontaining two indenyl groups. In yet another aspect, catalyst componentI can comprise an unbridged zirconium or hafnium based metallocenecompound containing a cyclopentadienyl group and an indenyl group.

Catalyst component I can comprise, in particular aspects of thisinvention, an unbridged metallocene compound having formula (I):

Within formula (I), M, Cp^(A), Cp^(B), and each X are independentelements of the unbridged metallocene compound. Accordingly, theunbridged metallocene compound having formula (I) can be described usingany combination of M, Cp^(A), Cp^(B), and X disclosed herein. Unlessotherwise specified, formula (I) above, any other structural formulasdisclosed herein, and any metallocene complex, compound, or speciesdisclosed herein are not designed to show stereochemistry or isomericpositioning of the different moieties (e.g., these formulas are notintended to display cis or trans isomers, or R or S diastereoisomers),although such compounds are contemplated and encompassed by theseformulas and/or structures.

In accordance with aspects of this invention, the metal in formula (I),M, can be Zr or Hf. Thus, M can be Zr in one aspect, and M can be Hf inanother aspect. Each X in formula (I) independently can be a monoanionicligand. In some aspects, suitable monoanionic ligands can include, butare not limited to, H (hydride), BH₄, a halide, a C₁ to C₃₆ hydrocarbylgroup, a C₁ to C₃₆ hydrocarboxy group, a C₁ to C₃₆ hydrocarbylaminylgroup, a C₁ to C₃₆ hydrocarbylsilyl group, a C₁ to C₃₆hydrocarbylaminylsilyl group, —OBR¹ ₂, or —OSO₂R¹, wherein R¹ is a C₁ toC₃₆ hydrocarbyl group. It is contemplated that each X can be either thesame or a different monoanionic ligand. Suitable hydrocarbyl groups,hydrocarboxy groups, hydrocarbylaminyl groups, hydrocarbylsilyl groups,and hydrocarbylaminylsilyl groups are disclosed, for example, in U.S.Pat. No. 9,758,600, incorporated herein by reference in its entirety.

Generally, the hydrocarbyl group which can be an X in formula (I) can bea C₁ to C₃₆ hydrocarbyl group, including a C₁ to C₃₆ alkyl group, a C₂to C₃₆ alkenyl group, a C₄ to C₃₆ cycloalkyl group, a C₅ to C₃₆ arylgroup, or a C₇ to C₃₆ aralkyl group. For instance, each X independentlycan be a C₁ to C₁₈ alkyl group, a C₂ to C₁₈ alkenyl group, a C₄ to C₁₈cycloalkyl group, a C₆ to C₁₈ aryl group, or a C₇ to C₁₈ aralkyl group;alternatively, each X independently can be a C₁ to C₁₂ alkyl group, a C₂to C₁₂ alkenyl group, a C₄ to C₁₂ cycloalkyl group, a C₆ to C₁₂ arylgroup, or a C₇ to C₁₂ aralkyl group; alternatively, each X independentlycan be a C₁ to C₁₀ to alkyl group, a C₂ to C₁₀ alkenyl group, a C₄ toC₁₀ cycloalkyl group, a C₆ to C₁₀ aryl group, or a C₇ to C₁₀ aralkylgroup; or alternatively, each X independently can be a C₁ to C₅ alkylgroup, a C₂ to C₅ alkenyl group, a C₅ to C₈ cycloalkyl group, a C₆ to C₈aryl group, or a C₇ to C₈ aralkyl group.

In particular aspects of this invention, each X independently can be ahalide or a C₁ to C₁₈ hydrocarbyl group. For instance, each X can be Cl.

In formula (I), Cp^(A) and Cp^(B) independently can be a substituted orunsubstituted cyclopentadienyl or indenyl group. In one aspect, Cp^(A)and Cp^(B) independently can be an unsubstituted cyclopentadienyl orindenyl group. Alternatively, Cp^(A) and Cp^(B) independently can be asubstituted indenyl or cyclopentadienyl group, for example, having up to5 substituents.

If present, each substituent on Cp^(A) and Cp^(B) independently can beH, a halide, a C₁ to C₃₆ hydrocarbyl group, a C₁ to C₃₆ halogenatedhydrocarbyl group, a C₁ to C₃₆ hydrocarboxy group, or a C₁ to C₃₆hydrocarbylsilyl group. Importantly, each substituent on Cp^(A) and/orCp^(B) can be either the same or a different substituent group.Moreover, each substituent can be at any position on the respectivecyclopentadienyl or indenyl ring structure that conforms with the rulesof chemical valence. In an aspect, the number of substituents on Cp^(A)and/or on Cp^(B) and/or the positions of each substituent on Cp^(A)and/or on Cp^(B) are independent of each other. For instance, two ormore substituents on Cp^(A) can be different, or alternatively, eachsubstituent on Cp^(A) can be the same. Additionally or alternatively,two or more substituents on Cp^(B) can be different, or alternatively,all substituents on Cp^(B) can be the same. In another aspect, one ormore of the substituents on Cp^(A) can be different from the one or moreof the substituents on Cp^(B), or alternatively, all substituents onboth Cp^(A) and/or on Cp^(B) can be the same. In these and otheraspects, each substituent can be at any position on the respectivecyclopentadienyl or indenyl ring structure. If substituted, Cp^(A)and/or Cp^(B) independently can have one substituent, or twosubstituents, or three substituents, or four substituents, and so forth.

Suitable hydrocarbyl groups, halogenated hydrocarbyl groups,hydrocarboxy groups, and hydrocarbylsilyl groups that can besubstituents are disclosed, for example, in U.S. Pat. No. 9,758,600,incorporated herein by reference in its entirety. For instance, thehalogenated hydrocarbyl group indicates the presence of one or morehalogen atoms replacing an equivalent number of hydrogen atoms in thehydrocarbyl group. The halogenated hydrocarbyl group often can be ahalogenated alkyl group, a halogenated alkenyl group, a halogenatedcycloalkyl group, a halogenated aryl group, or a halogenated aralkylgroup. Representative and non-limiting halogenated hydrocarbyl groupsinclude pentafluorophenyl, trifluoromethyl (CF₃), and the like.

Illustrative and non-limiting examples of unbridged metallocenecompounds having formula (I) and/or suitable for use as catalystcomponent I can include the following compounds (Ph=phenyl):

and the like, as well as combinations thereof.

Catalyst component I is not limited solely to unbridged metallocenecompounds such as described above. Other suitable unbridged metallocenecompounds are disclosed in U.S. Pat. Nos. 7,199,073, 7,226,886,7,312,283, and 7,619,047, which are incorporated herein by reference intheir entirety.

Referring now to catalyst component II, which can be a bridgedmetallocene compound. In one aspect, for instance, catalyst component IIcan comprise a bridged zirconium or hafnium based metallocene compound.In another aspect, catalyst component II can comprise a bridgedzirconium or hafnium based metallocene compound with an alkenylsubstituent. In yet another aspect, catalyst component II can comprise abridged zirconium or hafnium based metallocene compound with an alkenylsubstituent and a fluorenyl group. In still another aspect, catalystcomponent II can comprise a bridged zirconium or hathium basedmetallocene compound with a cyclopentadienyl group and a fluorenylgroup, and with an alkenyl substituent on the bridging group and/or onthe cyclopentadienyl group. Further, catalyst component II can comprisea bridged metallocene compound having an aryl group substituent on thebridging group.

Catalyst component II can comprise, in particular aspects of thisinvention, a bridged metallocene compound having formula (II):

Within formula (II), M, Cp, R^(X), R^(Y), E, and each X are independentelements of the bridged metallocene compound. Accordingly, the bridgedmetallocene compound having formula (II) can be described using anycombination of M, Cp, R^(X), R^(Y), E, and X disclosed herein. Theselections for M and each X in formula (II) are the same as thosedescribed herein above for formula (I). In formula (II), Cp can be asubstituted cyclopentadienyl, indenyl, or fluorenyl group. In oneaspect, Cp can be a substituted cyclopentadienyl group, while in anotheraspect, Cp can be a substituted indenyl group.

In some aspects, Cp can contain no additional substituents, e.g., otherthan bridging group E, discussed further herein below. In other aspects,Cp can be further substituted with one substituent, or two substituents,or three substituents, or four substituents, and so forth. If present,each substituent on Cp independently can be H, a halide, a C₁ to C₃₆hydrocarbyl group, a C₁ to C₃₆ halogenated hydrocarbyl group, a C₁ toC₃₆ hydrocarboxy group, or a C₁ to C₃₆ hydrocarbylsilyl group.Importantly, each substituent on Cp can be either the same or adifferent substituent group. Moreover, each substituent can be at anyposition on the respective cyclopentadienyl, indenyl, or fluorenyl ringstructure that conforms with the rules of chemical valence. In general,any substituent on Cp, independently, can be H or any halide, C₁ to C₃₆hydrocarbyl group, C₁ to C₃₆ halogenated hydrocarbyl group, C₁ to C₃₆hydrocarboxy group, or C₁ to C₃₆ hydrocarbylsilyl group described herein(e.g., as pertaining to substituents on Cp^(A) and Cp^(B) in formula(I)).

Similarly, R^(X) and R^(Y) in formula (II) independently can be H or anyhalide, C₁ to C₃₆ hydrocarbyl group, C₁ to C₃₆ halogenated hydrocarbylgroup, C₁ to C₃₆ hydrocarboxy group, or C₁ to C₃₆ hydrocarbylsilyl groupdisclosed herein (e.g., as pertaining to substituents on Cp^(A) andCp^(B) in formula (I)). In one aspect, for example, R^(X) and R^(Y)independently can be H or a C₁ to C₁₂ hydrocarbyl group. In anotheraspect, R^(X) and R^(Y) independently can be a C₁ to C₁₀ hydrocarbylgroup. In yet another aspect, R^(X) and R^(Y) independently can be H,Cl, CF₃, a methyl group, an ethyl group, a propyl group, a butyl group(e.g., t-Bu), a pentyl group, a hexyl group, a heptyl group, an octylgroup, a nonyl group, a decyl group, an ethenyl group, a propenyl group,a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, anoctenyl group, a nonenyl group, a decenyl group, a phenyl group, a tolylgroup, a benzyl group, a naphthyl group, a trimethylsilyl group, atriisopropylsilyl group, a triphenylsilyl group, or anallyldimethylsilyl group, and the like. In still another aspect, R^(X)and R^(Y) independently can be a methyl group, an ethyl group, a propylgroup, a butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a nonyl group, a decyl group, an ethenyl group, a propenylgroup, a butenyl group, a pentenyl group, a hexenyl group, a heptenylgroup, an octenyl group, a nonenyl group, a decenyl group, a phenylgroup, a tolyl group, or a benzyl group.

Bridging group E in formula (II) can be a bridging group having theformula >E^(A)R^(A)R^(B), wherein E^(A) can be C, Si, or Ge, and R^(A)and R^(B) independently can be H or a C₁ to C₁₈ hydrocarbyl group. Insome aspects of this invention, R^(A) and R^(B) independently can be aC₁ to C₁₂ hydrocarbyl group; alternatively, R^(A) and R^(B)independently can be a C₁ to C₈ hydrocarbyl group; alternatively, R^(A)and R^(B) independently can be a phenyl group, a C₁ to C₈ alkyl group,or a C₃ to C₈ alkenyl group; alternatively, R^(A) and R^(B)independently can be a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group, a hexyl group, a heptyl group, an octylgroup, a nonyl group, a decyl group, an ethenyl group, a propenyl group,a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, anoctenyl group, a nonenyl group, a decenyl group, a phenyl group, acyclohexylphenyl group, a naphthyl group, a tolyl group, or a benzylgroup; or alternatively, R^(A) and R^(B) independently can be a methylgroup, an ethyl group, a propyl group, a butyl group, a pentyl group, ahexyl group, a propenyl group, a butenyl group, a pentenyl group, ahexenyl group, a phenyl group, or a benzyl group. In these and otheraspects, R^(A) and R^(B) can be either the same or different.

Illustrative and non-limiting examples of bridged metallocene compoundshaving formula (II) and/or suitable for use as catalyst component II caninclude the following compounds (Me=methyl, Ph=phenyl; t-Bu=tert-butyl):

and the like, as well as combinations thereof.

Catalyst component II is not limited solely to the bridged metallocenecompounds such as described above. Other suitable bridged metallocenecompounds are disclosed in U.S. Pat. Nos. 7,026,494, 7,041,617,7,226,886, 7,312,283, 7,517,939, and 7,619,047, which are incorporatedherein by reference in their entirety.

According to an aspect of this invention, the weight ratio of catalystcomponent I to catalyst component II in the catalyst composition can bein a range from about 10:1 to about 1:10, from about 8:1 to about 1:8,from about 5:1 to about 1:5, from about 4:1 to about 1:4, from about 3:1to about 1:3; from about 2:1 to about 1:2, from about 1.5:1 to about1:1.5, from about 1.25:1 to about 1:1.25, or from about 1.1:1 to about1:1.1. In another aspect, catalyst component I is the major component ofthe catalyst composition, and in such aspects, the weight ratio ofcatalyst component I to catalyst component II in the catalystcomposition can be in a range from about 10:1 to about 1:1, from about5:1 to about 1.1:1, from about 2:1 to about 1.1:1, or from about 1.8:1to about 1.1:1.

Additionally, the dual catalyst system contains an activator. Forexample, the catalyst system can contain an activator-support, analuminoxane compound, an organoboron or organoborate compound, anionizing ionic compound, and the like, or any combination thereof. Thecatalyst system can contain one or more than one activator.

In one aspect, the catalyst system can comprise an aluminoxane compound,an organoboron or organoborate compound, an ionizing ionic compound, andthe like, or a combination thereof. Examples of such activators aredisclosed in, for instance, U.S. Pat. Nos. 3,242,099, 4,794,096,4,808,561, 5,576,259, 5,807,938, 5,919,983, and 8,114,946, thedisclosures of which are incorporated herein by reference in theirentirety. In another aspect, the catalyst system can comprise analuminoxane compound. In yet another aspect, the catalyst system cancomprise an organoboron or organoborate compound. In still anotheraspect, the catalyst system can comprise an ionizing ionic compound.

In other aspects, the catalyst system can comprise an activator-support,for example, an activator-support comprising a solid oxide treated withan electron-withdrawing anion. Examples of such materials are disclosedin, for instance, U.S. Pat. Nos. 7,294,599, 7,601,665, 7,884,163,8,309,485, 8,623,973, and 9,023,959, which are incorporated herein byreference in their entirety. For instance, the activator-support cancomprise fluorided alumina, chlorided alumina, bromided alumina,sulfated alumina, fluorided silica-alumina, chlorided silica-aluminabromided sulfated silica-alumina, fluorided silica-zirconia, chloridedsilica-zirconia, bromided silica-zirconia, sulfated silica-zirconia,fluorided silica titanic, fluorided-chlorided silica-coated alumina,fluorided silica-coated alumina, sulfated silica-coated alumina, orphosphated silica-coated alumina, and the like, as well as anycombination thereof. In some aspects, the activator-support can comprisea fluorided solid oxide and/or a sulfated solid oxide.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, impregnation with metals or metal ions (e.g.,zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof),and various calcining procedures and conditions are disclosed in, forexample, U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494, 6,300,271,6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816, 6,395,666,6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712, 6,632,894,6,667,274, 6,750,302, 7,294,599, 7,601,665, 7,884,163, and 8,309,485,which are incorporated herein by reference in their entirety. Othersuitable processes and procedures for preparing activator-supports(e.g., fluorided solid oxides, sulfated solid oxides, etc.) are wellknown to those of skill in the art.

The present invention can employ catalyst compositions containingcatalyst component I, catalyst component II, an activator (one or morethan one), and optionally, a co-catalyst. When present, the co-catalystcan include, but is not limited to, metal alkyl, or organometal,co-catalysts, with the metal encompassing boron, aluminum, zinc, and thelike. Optionally, the catalyst systems provided herein can comprise aco-catalyst, or a combination of co-catalysts. For instance, alkylboron, alkyl aluminum, and alkyl zinc compounds often can be used asco-catalysts in such catalyst systems. Representative boron compoundscan include, but are not limited to, tri-n-butyl borane,tripropylborane, triethylborane, and the like, and this includecombinations of two or more of these materials. While not being limitedthereto, representative aluminum compounds (e.g., organoaluminumcompounds) can include trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, and the like, aswell as any combination thereof. Exemplary zinc compounds (e.g.,organozinc compounds) that can be used as co-catalysts can include, butare not limited to, dimethylzinc, diethylzinc, dipropylzinc,dibutylzinc, dineopentylzinc, di(trimethylsilyl)zinc,di(triethylsilyl)zinc, di(triisoproplysilyl)zinc,di(triphenylsilyl)zinc, di(allyldimethylsilyl)zinc,di(trimethylsilylmethyl)zinc, and the like, or combinations thereof.Accordingly, in an aspect of this invention, the dual catalystcomposition can comprise catalyst component I, catalyst component II, anactivator-support, and an organoaluminum compound (and/or an organozinccompound).

In another aspect of the present invention, a catalyst composition isprovided which comprises catalyst component I, catalyst component II, anactivator-support, and an organoaluminum compound, wherein this catalystcomposition is substantially free of aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and/or other similarmaterials; alternatively, substantially free of aluminoxanes;alternatively, substantially free or organoboron or organoboratecompounds; or alternatively, substantially free of ionizing ioniccompounds. In these aspects, the catalyst composition has catalystactivity, discussed herein, in the absence of these additionalmaterials. For example, a catalyst composition of the present inventioncan consist essentially of catalyst component I, catalyst component II,an activator-support, and an organoaluminum compound, wherein no othermaterials are present in the catalyst composition which wouldincrease/decrease the activity of the catalyst composition by more thanabout 10% from the catalyst activity of the catalyst composition in theabsence of said materials.

Catalyst compositions of the present invention generally have a catalystactivity greater than about 250 grams of ethylene polymer (homopolymerand/or copolymer, as the context requires) gram of activator-support perhour (abbreviated g/g/hr). In another aspect, the catalyst activity canbe greater than about 350, greater than about 450, or greater than about550 g/g/hr. Yet, in another aspect, the catalyst activity can be greaterthan about 700 g/g/hr, greater than about 1000 g/g/hr, or greater thanabout 2000 g/g/hr, and often as high as 5000-10,000 g/g/hr. Illustrativeand non-limiting ranges for the catalyst activity include from about 500to about 5000, from about 750 to about 4000, or from about 1000 to about3500 g/g/hr, and the like. These activities are measured under slurrypolymerization conditions, with a triisobutylaluminum co-catalyst, usingisobutane as the diluent, at a polymerization temperature of about 95°C. and a reactor pressure of about 590 psig. Moreover, in some aspects,the activator-support can comprise sulfated alumina, fluoridedsilica-alumina, or fluorided silica-coated alumina, although not limitedthereto.

This invention further encompasses methods of making these catalystcompositions, such as, for example, contacting the respective catalystcomponents in any order or sequence. In one aspect, for example, thecatalyst composition can be produced by a process comprising contacting,in any order, catalyst component I, catalyst component II, and theactivator, while in another aspect, the catalyst composition can beproduced by a process comprising contacting, in any order, catalystcomponent I, catalyst component II, the activator, and the co-catalyst.

Olefin polymers (e.g., ethylene polymers) can be produced from thedisclosed catalyst systems using any suitable olefin polymerizationprocess using various types of polymerization reactors, polymerizationreactor systems, and polymerization reaction conditions. One such olefinpolymerization process for polymerizing olefins in the presence of acatalyst composition of the present invention can comprise contactingthe catalyst composition with an olefin monomer and optionally an olefincomonomer (one or more) in a polymerization reactor system underpolymerization conditions to produce an olefin polymer, wherein thecatalyst composition can comprise, as disclosed herein, catalystcomponent I, catalyst component II, an activator, and an optionalco-catalyst. This invention also encompasses any olefin polymers (e.g.,ethylene polymers) produced by any of the polymerization processesdisclosed herein.

As used herein, a “polymerization reactor” includes any polymerizationreactor capable of polymerizing (inclusive of oligomerizing) olefinmonomers and comonomers (one or more than one comonomer) to producehomopolymers, copolymers, terpolymers, and the like. The various typesof polymerization reactors include those that can be referred to as abatch reactor, slurry reactor, gas-phase reactor, solution reactor, highpressure reactor, tubular reactor, autoclave reactor, and the like, orcombinations thereof; or alternatively, the polymerization reactorsystem can comprise a slurry reactor, a gas-phase reactor, a solutionreactor, or a combination thereof. The polymerization conditions for thevarious reactor types are well known to those of skill in the art. Gasphase reactors can comprise fluidized bed reactors or staged horizontalreactors. Slurry reactors can comprise vertical or horizontal loops.High pressure reactors can comprise autoclave or tubular reactors.Reactor types can include batch or continuous processes. Continuousprocesses can use intermittent or continuous product discharge.Polymerization reactor systems and processes also can include partial orfull direct recycle of unreacted monomer, unreacted comonomer, and/ordiluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (2 reactors, more than 2 reactors, etc.) of the sameor different type. For instance, the polymerization reactor system cancomprise a slurry reactor, a gas-phase reactor, a solution reactor, or acombination of two or more of these reactors. Production of polymers inmultiple reactors can include several stages in at least two separatepolymerization reactors interconnected by a transfer device making itpossible to transfer the polymers resulting from the firstpolymerization reactor into the second reactor. The desiredpolymerization conditions in one of the reactors can be different fromthe operating conditions of the other reactor(s). Alternatively,polymerization in multiple reactors can include the manual transfer ofpolymer from one reactor to subsequent reactors for continuedpolymerization. Multiple reactor systems can include any combinationincluding, but not limited to, multiple loop reactors, multiple gasphase reactors, a combination of loop and gas phase reactors, multiplehigh pressure reactors, or a combination of high pressure with loopand/or gas phase reactors. The multiple reactors can be operated inseries, in parallel, or both. Accordingly, the present inventionencompasses polymerization reactor systems comprising a single reactor,comprising two reactors, and comprising more than two reactors. Thepolymerization reactor system can comprise a slurry reactor, a gas-phasereactor, a solution reactor, in certain aspects of this invention, aswell as multi-reactor combinations thereof.

According to one aspect, the polymerization reactor system can compriseat least one loop slurry reactor comprising vertical or horizontalloops. Monomer, diluent, catalyst, and comonomer can be continuously fedto a loop reactor where polymerization occurs. Generally, continuousprocesses can comprise the continuous introduction of monomer/comonomer,a catalyst, and a diluent into a polymerization reactor and thecontinuous removal from this reactor of a suspension comprising polymerparticles and the diluent. Reactor effluent can be flashed to remove thesolid polymer from the liquids that comprise the diluent, monomer and/orcomonomer. Various technologies can be used for this separation stepincluding, but not limited to, flashing that can include any combinationof heat addition and pressure reduction, separation by cyclonic actionin either a cyclone or hydrocyclone, or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and8,822,608, each of which is incorporated herein by reference in itsentirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used.

According to yet another aspect, the polymerization reactor system cancomprise at least one gas phase reactor (e.g., a fluidized bed reactor).Such reactor systems can employ a continuous recycle stream containingone or more monomers continuously cycled through a fluidized bed in thepresence of the catalyst under polymerization conditions. A recyclestream can be withdrawn from the fluidized bed and recycled back intothe reactor. Simultaneously, polymer product can be withdrawn from thereactor and new or fresh monomer can be added to replace the polymerizedmonomer. Such gas phase reactors can comprise a process for multi-stepgas-phase polymerization of olefins, in which olefins are polymerized inthe gaseous phase in at least two independent gas-phase polymerizationzones while feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. Representative gasphase reactors are disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790,5,436,304, 7,531,606, and 7,598,327, each of which is incorporated byreference in its entirety herein.

According to still another aspect, the polymerization reactor system cancomprise a high pressure polymerization reactor, e.g., can comprise atubular reactor or an autoclave reactor, Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect, the polymerization reactor system cancomprise a solution polymerization reactor wherein the monomer/comonomerare contacted with the catalyst composition by suitable stirring orother means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer/comonomer can bebrought in the vapor phase into contact with the catalytic reactionproduct, in the presence or absence of liquid material. Thepolymerization zone can be maintained at temperatures and pressures thatwill result in the formation of a solution of the polymer in a reactionmedium. Agitation can be employed to obtain better temperature controland to maintain uniform polymerization mixtures throughout thepolymerization zone. Adequate means are utilized for dissipating theexothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control. Depending upon thedesired properties of the olefin polymer, hydrogen can be added to thepolymerization reactor as needed (e.g., continuously, pulsed, etc.).

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. Various polymerization conditions can beheld substantially constant, for example, for the production of aparticular grade of the olefin polymer (or ethylene polymer). A suitablepolymerization temperature can be any temperature below thede-polymerization temperature according to the Gibbs Free energyequation. Typically, this includes from about 60° C. to about 280° C.,for example, or from about 60° C. to about 120° C., depending upon thetype of polymerization reactor(s). In some reactor systems, thepolymerization temperature generally can be within a range from about70° C. to about 100° C., or from about 75° C. to about 95° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig (6.9 MPa). Pressure forgas phase polymerization is usually at about 200 to 500 psig (1.4 MPa to3.4 MPa). High pressure polymerization in tubular or autoclave reactorsis generally run at about 20,000 to 75,000 psig (138 to 517 MPa).Polymerization reactors can also be operated in a supercritical regionoccurring at generally higher temperatures and pressures. Operationabove the critical point of a pressure/temperature diagram(supercritical phase) can offer advantages to the polymerizationreaction process.

Olefin monomers that can be employed with catalyst compositions andpolymerization processes of this invention typically can include olefincompounds having from 2 to 30 carbon atoms per molecule and having atleast one olefinic double bond, such as ethylene or propylene. In anaspect, the olefin monomer can comprise a C₂-C₂₀ olefin; alternatively,a C₂-C₂₀ alpha-olefin; alternatively, a C₂-C₁₀ olefin; alternatively, aC₂-C₁₀ alpha-olefin; alternatively, the olefin monomer can compriseethylene; or alternatively, the olefin monomer can comprise propylene toproduce a polypropylene homopolymer or a propylene-based copolymer).

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer and the olefin comonomer independently can comprise, forexample, a C₂-C₂₀ alpha-olefin. In some aspects, the olefin monomer cancomprise ethylene or propylene, which is copolymerized with at least onecomonomer (e.g., a C₂-C₂₀ alpha-olefin, a C₃-C₂₀ alpha-olefin, etc.).According to one aspect of this invention, the olefin monomer used inthe polymerization process can comprise ethylene. In this aspect, thecomonomer can comprise a C₃-C₁₀ alpha-olefin; alternatively, thecomonomer can comprise 1-butene, 1-pentene, -hexene, 1-octene, 1-decene,styrene, or any combination thereof; alternatively, the comonomer cancomprise 1-butene. 1-hexene, 1-octene, or any combination thereof;alternatively, the comonomer can comprise 1-butene; alternatively, thecomonomer can comprise 1-hexene, or alternatively, the comonomer cancomprise 1-octene.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Melt index (MI, g/10 min) care can be determined in accordance with ASTMD1238 at 190° C. with a 2,160 gram weight, and. high load melt index(HLMI, g/10 min) was determined in accordance with ASTM D1238 at 190° C.with a 21,600 gram weight. Density was determined in grams per cubiccentimeter (g/cm³) on a compression molded sample, cooled at 15° C. perminute, and conditioned for 40 hours at room temperature in accordancewith ASTM D1505 and ASTM D4703. ESCR was determined in accordance withASTM D1693, condition B, with 10% igepal.

Molecular weights and molecular weight distributions were obtained usinga PL-GPC 220 (Polymer Labs, an Agilent Company) system equipped with aIR4 detector (Polymer Char, Spain) and three Styragel HMW-6E GPC columns(Waters, MA) running at 145° C. The flow rate of the mobile phase1,2,4-trichlorobenzene (TCB) containing 0.5 g/L2,6-di-t-butyl-4-methylphenol (BHT) was set at 1 mL/min, and polymersolution concentrations were in the range of 1.0-1.5 mg/mL, depending onthe molecular weight. Sample preparation was conducted at 150° C. fornominally 4 hr with occasional and gentle agitation, before thesolutions were transferred to sample vials for injection. An injectionvolume of about 200 μL was used. The integral calibration method wasused to deduce molecular weights and molecular weight distributionsusing a Chevron Phillips Chemical Company's HDPE polyethylene resin,MARLEX® BHB5003, as the broad standard. The integral table of the broadstandard was pre-determined in a separate experiment with SEC-MALS. Mnis the number-average molecular weight, Mw is the weight-averagemolecular weight, Mz is the z-average molecular weight Mv isviscosity-average molecular weight, and Mp is the peak molecular weight(location, in molecular weight, of the highest point of the molecularweight distribution curve). IVc is the intrinsic viscosity [η], which iscalculated based on Equation 1:

[η]=K Mv^(a)  Equation 1

where Mv is the viscosity-average molecular weight, K and a areMark-Houwink constants for the polymer of interest. For polyethylene, Kand a are 3.95E-04 (dL/g) and 0.726 (unitless), respectively. Mv iscalculated based on Equation 2:

$\begin{matrix}{M_{V} = \left\lbrack \frac{\sum{w_{i}M_{i}^{a}}}{\sum w_{i}} \right\rbrack^{1/a}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

where w_(t) and M_(i) are weight fraction and molecular weight of slicei, respectively.

Melt rheological characterizations were performed as follows.Small-strain (less than 10%) oscillatory shear measurements wereperformed on an Anton Paar MCR rheometer using parallel-plate geometry.All theological tests were performed at 190° C. The complex viscosity|η*| versus frequency (ω) data were then curve fitted using the modifiedthree parameter Carreau-Yasuda (CY) empirical model to obtain the zeroshear viscosity—η₀, characteristic viscous relaxation time—τ_(η), andthe breadth parameter—a (CY-a parameter). The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$

-   wherein: |η*(ω)|=magnitude of complex shear viscosity;    -   η₀=zero shear viscosity;    -   τ_(η)=viscous relaxation time (Tau(η));    -   a=“breadth” parameter (CY-a parameter);    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters can be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition,John Wiley Sons (1987); each of which is incorporated herein byreference in its entirety. The viscosity at HLMI (eta @ HLMI or η @HLMI) is the viscosity at the HLMI stress for the polymer at its HLMI.

Short chain branch (SCB) content and short chain branching distribution(SCBD) across the molecular weight distribution can be determined via anIR5-detected GPC system (IR5-GPC), wherein the GPC system is a PL220GPC/SEC system (Polymer Labs, an Agilent company) equipped with threeStyragel HMW-6E columns (Waters, Mass.) for polymer separation. Athermoelectric-cooled IR5 MCT detector (IR5) (Polymer Char, Spain) isconnected to the GPC columns via a hot-transfer line. Chromatographicdata are obtained from two output ports of the IR5 detector. First, theanalog signal goes from the analog output port to a digitizer beforeconnecting to Computer “A” for molecular weight determinations via theCirrus software (Polymer Labs, now an Agilent Company) and the integralcalibration method using a broad MWD HDPE Marlex™ BHB5003 resin (ChevronPhillips Chemical) as the broad molecular weight standard. The digitalsignals, on the other hand, go via a USB cable directly to Computer “B”where they are collected by a LabView data collection software providedby Polymer Char. Chromatographic conditions are set as follows: columnoven temperature of 145° C.; flowrate of 1 mL/min; injection volume of0.4 mL; and polymer concentration of about 2 mg/mL, depending on samplemolecular weight. The temperatures for both the hot-transfer line andIR5 detector sample cell are set at 150° C., while the temperature ofthe electronics of the IR5 detector is set at 60° C. Short chainbranching content is determined via an in-house method using theintensity ratio of CH₃ (I_(CH3)) to CH₂ (I_(CH2)) coupled with acalibration curve. The calibration curve is a plot of SCB content(x_(SCB)) as a function of the intensity ratio of I_(CH3)/I_(CH2). Toobtain a calibration curve, a group of polyethylene resins (no less than5) of SCB level ranging from zero to ca. 32 SCB/1,000 total carbons (SCBStandards) is used. All these SCB Standards have known SCB levels andflat SCBD profiles pre-determined separately by NMR and thesolvent-gradient fractionation coupled with NMR (SGF-NMR) methods. UsingSCB calibration curves thus established, profiles of short chainbranching distribution across the molecular weight distribution areobtained for resins fractionated by the IR5-GPC system under exactly thesame chromatographic conditions as for these SCB standards. Arelationship between the intensity ratio and the elution volume isconverted into SCB distribution as a function of MWD using apredetermined SCB calibration curve intensity ratio of I_(CH3)/I_(CH2)vs. SCB content) and MW calibration curve (i.e., molecular weight vs.elution time) to convert the intensity ratio of I_(CH3)/I_(CH2) and theelution time into SCB content and the molecular weight, respectively.

The long chain branches (LCBs) per 1000 total carbon atoms of theoverall polymer can be calculated using the method of Janzen and Colby(J. Mol. Struct., 485/486, 569-584 (1999), incorporated herein byreference in its entirety), from values of zero shear viscosity,(determined from the Carreau-Yasuda model, described hereinabove), andmeasured values of Mw obtained using a Dawn EOS multiangle lightscattering detector (Wyatt).

Blow molding evaluations of Examples 1-10 were performed on a Sterlingblow molding machine with the following specifications. These particularequipment and processing conditions were chosen because the blow moldingperformance and properties so obtained are typically representative ofthose obtained from larger, commercial scale blow molding operations.The extruder screw diameter was 3″, the L/D Ratio was 24:1, the drivemotor was a 75 HP DC drive, and the maximum plasticizing capacity wasabout 350 lb polyethylene per hr. The extruder was equipped with adynicso pressure indicator, four heating zones with air cooling, and asmooth bore barrel with liquid cooling in the teed zone.

The accumulator head (FIFO Design) had a maximum shot capacity of 10 lb,a die bushing diameter maximum and minimum of 8″ and 1″ (respectively),where 1″ thru 3½″ is converging, and 4″ thru 8″ is diverging. The blowmolding machine was also equipped with a 100 point MACO programmer.

For Examples 1-10, all extruder and head zones were set at 390° F. Themold was a 9-gallon bottle (Fremont Plastics Mold, 42″ circumference),and 4.5″ diverging die head with a 30 degree land angle was used. Aconstant push-out speed was used. The mold temperature was 50-60° F. Thetimer settings were a 0.5 sec blow delay, a 0 sec preblow, and a 0.25sec clamp close delay. Air pressure was approximately 90 psig. Theminimum wall thickness of the parts was in the 45-50 mil range, and thedie gap was 0.196″. Parts were produced at an extruder speed of 30 RPMand a blow time of 90 sec.

The weight of the product produced (part weight) was recorded, and thewidth of the flashing at the top of the product (layflat top) and thebottom of the product (lay-flat bottom) was measured. Die swell (parisonsize versus die size) and weight swell (change in part weight atconstant die gap and parison speed) can be determined. The meltstrengths of the polymers were compared via a hang time test using a0.089″ die gap and 20 RPM extruder speed. A parison was extruded andallowed to hang; the extruder speed was turned to zero while the parisonwas hanging. The time from the end of the shot to the time the parisontore away from the bushing was recorded as the hang time.

Fluorided silica-coated alumina activator-supports used in Examples 1-8were prepared as follows. Bohemite was obtained from W. R. Grace &Company under the designation “Alumina A” and having a surface area ofabout 300 m²/g, a pore volume of about 1.3 mL/g, and an average particlesize of about 100 microns. The alumina was first calcined in dry air atabout 600° C. for approximately 6 hours, cooled to ambient temperature,and then contacted with tetraethylorthosilicate in isopropanol to equal25 wt. % SiO₂. After drying, the silica-coated alumina was calcified at600° C. for 3 hours. Fluorided silica-coated alumina (7 wt. % F) wasprepared by impregnating the calcined silica-coated alumina with anammonium bifluoride solution in methanol, drying, and then calcining for3 hours at 600° C. in dry air. Afterward, the fluorided silica-coatedalumina was collected and stored under dry nitrogen, and was usedwithout exposure to the atmosphere.

Pilot plant polymerizations were conducted in a 30-gallon slurry loopreactor at a production rate of approximately 33 pounds of polymer perhour. Polymerization work was carried out under continuous particle formprocess conditions in a loop reactor (also referred to as a slurryprocess) by contacting a dual metallocene solution in isobutane, anorganoaluminum solution (triisobutylaluminum, TIBA), and anactivator-support (fluorided silica-coated alumina) in a 1-L stirredautoclave with continuous output to the loop reactor. The TIBA and dualmetallocene solutions were fed as separate streams into a tee upstreamof the autoclave where they contacted each other. The activator-supportwas flushed with isobutane at a point after the aforementioned tee,contacting the organoaluminum/metallocene mixture and flowing togetherto the autoclave. The isobutane flush used to transport theactivator-support into the autoclave was set at a rate that would resultin a residence time of approximately 30 minutes in the autoclave. Thetotal flow from the autoclave then entered the loop reactor.

Ethylene used was polymerization grade ethylene obtained from AirGaswhich was purified through a column of alumina-zeolite adsorbent(activated at 230-290° C. in nitrogen). Polymerization grade 1-hexene(obtained from Chevron Phillips Chemical Company) which was purified bydistillation and passed through a column of alumina-zeolite absorbentactivated at 230-290° C. in nitrogen. The loop reactor was liquid full,15.2 cm diameter, having a volume of 30 gallons (113.6 liters). Liquidisobutane was used as the diluent. Hydrogen was added at about0.001-0.004 lb/hr to tune the molecular weight and/or HLMI of thepolymer product. The isobutane was polymerization grade isobutane(obtained from Enterprise) that was further purified by distillation andsubsequently passed through a column of alumina, (activated at 230-290°C. in nitrogen). Co-catalyst TIBA was obtained as a 10-12 weight %solution in hydrocarbon and was further diluted to 2 weight percent inisobutane. The co-catalyst was added in a concentration of approximately125 ppm based on the weight of the diluent in the polymerizationreactor.

Reactor conditions included a reactor pressure around 590 psig, a mol %ethylene of 11-13% (based on isobutane diluent), and a polymerizationtemperature of 93-100° C. The reactor was operated to have a residencetime of about 0.8-1.3 hr. Metallocene concentrations in the reactor werewithin a range of about 1.5 to 2.5 parts per million (ppm) by weight ofthe diluent. The activator-support (fluorided silica-coated alumina) wasfed to the reactor at the rate of approximately 0.015-0.03 lb per hour.Polymer was removed from the reactor at the rate of about 33 lb/hr andpassed through a flash chamber and a purge column. Nitrogen was fed tothe purge column to ensure the fluff was hydrocarbon free. Thestructures for MET 1 and MET 2, used in Examples 1-8, are shown below:

Table I summarizes certain information relating to the polymerizationexperiments of Examples 1-8. Each of Examples 1-8 utilized a dualcatalyst system containing MET 1 and MET 2 at the relative amountslisted in Table I.

Examples 1-10

Example 9 was a broad monomodal copolymer resin, having a nominal 12HLMI and 0.949 density, produced using a chromium-based catalyst system(Chevron-Phillips Chemical Company LP). Example 10 was a broad bimodalcopolymer resin, having a nominal 5 HLMI and 0.955 density, producedusing a metallocene-based catalyst system (Chevron-Phillips ChemicalCompany LP).

FIG. 1 illustrates the bimodal molecular weight distributions (amount ofpolymer versus the logarithm of molecular weight) of the polymers ofExamples 1-4, FIG. 2 illustrates the bimodal molecular weightdistributions of the polymers of Examples 5-8, FIG. 3 illustrates themolecular weight distributions of the polymers of Examples 1, 5, and 9,Table I summarizes polymer HLMI, density, and ESCR properties, and TableII summarizes certain molecular weight characteristics of the polymersof Examples 1-9. The polymers of Examples 1-8 had densities ranging from0.956 to 0.96 g/cm³, HLMI values ranging from 9 to 14 g/10 min, ESCRvalues greater than 1000 hours, Mw values ranging from 330,000 to400,000 g/mol, Mn values ranging from 20,000 to 33,000 g/mol, and IVcvalues ranging from 3 to 3.6 dL/g. In contrast, the unimodal chromiumpolymer of Example 9 had lower Mw, Mn, and IVc values.

Table III summarizes certain rheological characteristics at 190° C. forthe polymers of Examples 1-9. Surprisingly, many of themetallocene-based polymers (Examples 1-8) had roughly equivalentprocessability to that of the chromium-based polymer (Example 9). Thepolymers of Examples 1-8 had η @ HLMI values ranging from 1400 to about4000 Pa-sec, and tan δ values at 0.1 sec⁻¹ ranging from 0.7 to 0.96degrees.

Table IV summarizes the blow molding performance of Examples 1-4 and9-10. Using the chromium polymer of Example 9 as a benchmark, it was canbe seen that comparative Example 10, while having good melt strength,had unacceptably high extrusion pressure (psig) and cycle time (sec),and low output rate (lb/hr). Moreover, in addition to excessive dieswell (layflat dimensions much larger than 10 inches), blow moldedproducts produced from Example 9 had poor surface aesthetics, withnoticeable surface distortions, lines, and streaking. In contrast, thepolymers of Examples 1-4 performed similarly to that of the chromiumpolymer of Example 9. Examples 1-4 had excellent processability(pressure, output rate), comparable die swell and hang time, andunexpectedly, lower cycle times (by 5-10%)—which translates into theproduction of more parts per hour. Examples 5-8 also were evaluatedsimilarly, and cycle time reductions of over 20% were found.

The blow molding products of Examples 1-10 also were evaluated forsurface aesthetics. Panels of the blow molded parts were evaluated, withthe panels being sections of the part with a width that is one-half thecircumference of the mold used in blow molding and 1 inch in height.Lesser surface defects were defined as minor discrepancies in thesurface appearance, such as a streak, where the color and/or texture ofthe part varies irregularly. Protrusions or severe surface defects weredefined as critical surface defects caused by distended strands or thinplates of polymer; the presence of such defects can render a blow moldedpart unusable. The blow molded parts of Example 10 had more than 200lesser surface defects and greater than 10 protrusions or severe surfacedefects in the panel, while the blow molded parts of Examples 1-4 weresurprisingly better, with 75-150 lesser surface defects and from 1-9protrusions or severe surface defects in the panel. The blow moldedproducts of Examples 5-8, unexpectedly, were even better, with only10-75 lesser surface defects and no (zero) protrusions or severe surfacedefects in the panel. As a benchmark, the blow molded products ofExample 9 also had no protrusions or severe surface defects in thepanel, and generally less than 10 less surface defects.

TABLE I Examples 1-8 - Polymerization Data and Polymer HLMI, Density,and ESCR lb H₂/ 1-hexene ESCR MET 2/MET 1 1000 lb C₂H₄ (lb/lb TIBA HLMIDensity (condition B, Example (ppm) C₂H₄ (mol %) C₂H₄) (ppm) (g/10 min)(g/cc) 10%, hr) 1 0.75/1.21 0.053 12.02 0.01 125 9.2 0.9565 >1000 20.67/1.10 0.053 11.65 0.01 125 11.0 0.9570 >1000 3 0.69/1.10 0.053 12.830.01 125 11.4 0.9582 >1000 4 0.75/1.22 0.053 12.47 0.01 125 10.20.9571 >1000 5 0.88/1.01 0.088 12.41 0.01 125 9.3 0.9588 >1000 60.88/1.03 0.088 12.60 0.01 125 11.9 0.9591 >1000 7 0.89/1.03 0.088 12.440.01 125 10.7 0.9586 >1000 8 0.84/1.08 0.088 12.01 0.01 125 13.30.9592 >1000 Note - The ESCR (condition B, 10%) for Example 9 was 72hours.

TABLE II Examples 1-9 - Molecular Weight Characterization (g/mol)Example Mn/1000 Mw/1000 Mz/1000 Mv/1000 Mp/1000 Mw/Mn Mz/Mw IB IVc 131.43 377.5 2322 262.3 71.3 12.01 6.15 1.35 3.39 2 31.54 359.0 2528244.9 73.1 11.38 7.04 1.27 3.23 3 32.83 338.4 2286 233.7 74.0 10.31 6.751.28 3.12 4 31.76 346.3 2192 241.7 75.0 10.90 6.33 1.31 3.20 5 23.57394.1 2225 273.2 59.1 16.72 5.65 1.52 3.50 6 22.41 354.9 2109 245.6 57.615.84 5.94 1.50 3.24 7 23.77 358.3 2051 249.5 54.8 15.07 5.72 1.53 3.278 23.42 335.2 2019 232.0 58.3 14.31 6.02 1.46 3.10 9 20.83 183.5 1064140.1 76.6 8.81 5.80 1.60 2.15

TABLE III Examples 1-9 - Rheological Characterization at 190° C. Zeroshear Tau (η) CY-a η @ 0.1 Tan d @ 0.1 η @ 100 Tan d @ 100 η @ HLMIExample (Pa-sec) (sec) parameter (Pa-sec) (degrees) (Pa-sec) (degrees)(Pa-sec) 1 2.86E+13 5.81E+08 0.059 2.00E+05 0.711 2461 0.583 3797 25.17E+19 1.19E+14 0.031 1.34E+05 0.762 2091 0.682 2301 3 9.17E+181.47E+13 0.031 1.26E+05 0.779 2039 0.694 2152 4 3.40E+17 2.20E+12 0.0371.54E+05 0.742 2222 0.650 2730 5 4.54E+06 9.00E+01 0.321 2.71E+05 0.8602313 0.366 3971 6 4.34E+06 8.71E+01 0.278 2.05E+05 0.914 2067 0.400 23967 2.53E+06 4.73E+01 0.343 2.36E+05 0.952 2192 0.368 3140 8 8.95E+061.99E+02 0.227 1.77E+05 0.874 1894 0.433 1691 9 8.09E+06 2.97E+01 0.1388.40E+04 1.210 2140 0.692 2436

TABLE IV Examples 1-4 and 9-10 - Blow Molding Performance ComparisonExample 9 10 1 2 3 4 HLMI 12.2 5.2 9.2 11.0 11.4 10.2 (g/10 min) Density0.949 0.955 0.957 0.957 0.958 0.957 (g/cc) Part Weight 1805 2132 18842004 1959 1983 (g) Layflat 10.00 10.69 9.71 10.09 9.89 10.17 Top (in)Layflat 10.09 10.49 9.26 9.80 9.74 9.66 Bottom (in) Cycle Time 229 344213 205 212 213 (sec) Pressure 1720 2050 2080 1710 1640 1840 (psig)Output @ 173 136 164 173 172 167 50 rpm (lb/hr) Hang Time 30 54 33 27 2625 (sec)

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, can “consist essentially of” or “consist of”):

Aspect 1. An ethylene polymer having (or characterized by):

a density in a range from about 0.952 to about 0.965 a/cm³;

a high load melt index (HLMI) in a range from about 5 to about 25 g/10min;

a weight-average molecular weight (Mw) in a range from about 275,000 toabout 450,000 g/mol;

a number-average molecular weight (Mn) in a range from about 15,000 toabout 40,000 g/mol;

a viscosity at HLMI (eta @ HLMI or η @ HLMI) in a range from about 1400to about 4000 Pa-sec; and

a tan δ (tan d or tangent delta) at 0.1 sec⁻¹ in a range from frothabout 0.65 to about 0.98 degrees.

Aspect 2. An ethylene polymer having (or characterized by):

a density in a range from about 0.952 to about 0.965 g/cm³;

a HLMI in a range from about 5 to about 25 g/10 min;

a Mw in a range from about 275,000 to about 450,000 g/mol;

a Mn in a range from about 15,000 to about 28,000 g/mol; and

a η @ HLMI in a range from about 1400 to about 4000 Pa-sec.

Aspect 3. The polymer defined in aspect 1 or 2, wherein the ethylenepolymer has an environmental stress crack resistance (ESCR) in any rangedisclosed herein, e.g., at least 250 hours, at least 500 hours, at least1,000 hours, at least 1,500 hours, at least 2,000 hours, etc.

Aspect 4. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a melt index (MI) in any rangedisclosed herein, e.g., from 0 to about 0.6, from 0 to about 0.3, from 0to about 0.2, from 0 to about 0.1 g/10 min, etc.

Aspect 5. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a HLMI in any range disclosed herein,e.g., front about 5 to about 20, from about 5 to about 18, from about 6to about 16, from about 7 to about 15 g/10 min, etc.

Aspect 6. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a density in any range disclosedherein, e.g., from about 0.952 to about 0.962, from about 0.952 to about0.96, from about 0.954 to about 0.965, from about 0.954 to about 0.962,from about 0.954 to about 0.96 g/cm³, etc.

Aspect 7. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has less than about 0.008 long chainbranches (LCBs) per 1000 total carbon atoms, e.g., less than about 0.005LCBs, less than about 0.003 LCBs, etc.

Aspect 8. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a reverse comonomer distribution, e.g.,the number of short chain branches (SCBs) per 1000 total carbon atoms ofthe polymer at Mw is greater than at Mn, the number of SCBs per 1000total carbon atoms of the polymer at Mz is greater than at Mw, thenumber of SCBs per 1000 total carbon atoms of the polymer at Mz isgreater than at Mn, etc.

Aspect 9. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mp in any range disclosed herein,e.g., from about 45,000 to about 85,000, from about 45,000 to about65,000, from about 50,000 to about 80,000, from about 50,000 to about62,000 g/mol, etc.

Aspect 10. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mw in any range disclosed herein,e.g., from about 275,000 to about 425,000, from about 275,000 to about400,000, from about 300,000 to about 450,000, from about 300,000 toabout 425,000, from about 300,000 to about 400,000, from about 325,000to about 450,000, from about 325,000 to about 425,000, from about325,000 to about 400,000 g/mol, etc.

Aspect 11. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mn in any range disclosed herein,e.g., from about 15,000 to about 40,000, from about 15,000 to about35,000, from about 15,000 to about 28,000, from about 17,000 to about40,000, from about 17,000 to about 35,000, from about 17,000 to about27,000 g/mol, etc.

Aspect 12. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mz in any range disclosed herein,e.g., from about 1,500,000 to about 3,000,000, from about 1,750,000 toabout from about 1,500,000 to about 2,750,000, from about 1,750,000 toabout 2,750,000, from about 1,850,000 to about 2,750,000 g/mol, etc.

Aspect 13. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of Mw/Mn in any range disclosedherein, e.g., from about 7 to about 20, from about 7 to about 18, fromabout 8 to about 20, from about 8 to about 18, from about 10 to about20, from about 10 to about 18, etc.

Aspect 14. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of Mz/Mw in any range disclosedherein, e.g., from about 4.5 to about 8, from about 4.5 to about 7.5,from about 5 to about 7, etc.

Aspect 15. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a CY-a parameter in any range disclosedherein, e.g., from about 0.1 to about 0.45, from about 0.15 to about0.4, from about 0.18 to about 0.36, from about 0.2 to about 0.35, etc.

Aspect 16. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a viscosity at HLMI (eta @ HLMI or η @HLMI) in any range disclosed herein, e.g., from about 1400 to about4000, from about 1500 to about 4000, from about 1600 to about 4000, fromabout 1400 to about 3900, from about 1500 to about 3900, from about 1600to about 3900 Pa-sec, etc.

Aspect 17. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a viscosity at 100 sec⁻¹ (eta @ 100 orη @ 100) in any range disclosed herein, e.g., from about 1500 to about3000, from about 1600 to about 2800, from about 1700 to about 2700, fromabout 1650 to about 2650, from about 1750 to about 2500 Pa-sec, etc.

Aspect 18. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a zero-shear viscosity in any rangedisclosed herein, e.g., greater than or equal to about 5×10⁵, greaterthan or equal to about 7.5×10⁵, greater than or equal to about 1×10⁶, ina range from about 1×10⁶ to about 1×10⁷ Pa-sec, etc.

Aspect 19. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a tan δ at 0.1 sec⁻¹ in any rangedisclosed herein, e.g., from about 0.65 to about 0.98 degrees, fromabout 0.7 to about 0.97 degrees, from about 0.8 to about 0.98 degrees,from about 0.82. to about 0.97 degrees, etc.

Aspect 20. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has an IVc in any range disclosed herein,e.g., from about 2.9 to about 3.7, from about 3 to about 3.6, from about3.1 to about 3.5 dL/g, etc.

Aspect 21. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of Mn/IVc in any rangedisclosed herein, e.g., from about 5.5 to about 12, from about 6 toabout 10, from about 5.5 to about 8.2, from about 6 to about 8, etc.

Aspect 22. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of η @ 0.1/η @ 100 in any rangedisclosed herein, e.g., from about 50 to about 150, from about 60 toabout 130, from about 85 to about 130, from about 90 to about 120, etc.

Aspect 23. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a part weight in any range disclosedherein, e.g., from about 1800 to about 2500, from about 1800 to about2200, from about 1800 to about 2100, from about 1850 to about 2100, fromabout 1850 to about 2050 g, etc.

Aspect 24. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a layflat (top) in any range disclosedherein, e.g., from about 9.3 to about 10.5, from about 9.5 to about10.5, from about 9.6 to about 10.3 inches, etc.

Aspect 25. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a cycle time in any range disclosedherein, e.g., from about 150 to about 300, from about 150 to about 275,from about 160 to about 280, from about 160 to about 260 seconds, etc.

Aspect 26. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a bimodal molecular weightdistribution.

Aspect 27. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer is a single reactor product, e.g., not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics.

Aspect 28. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/α-olefin copolymer.

Aspect 29. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/1-butene copolymer,an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.

Aspect 30. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/1-hexene copolymer.

Aspect 31. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer contains, independently, less than 0.1 ppm(by weight), less than 0.08 ppm, less than 0.05 ppm, less than 0.03 ppm,etc., of chromium and titanium.

Aspect 31. An article comprising the ethylene polymer defined in any oneof the preceding aspects.

Aspect 33. An article comprising the ethylene polymer defined in any oneof aspects 1-31, wherein the article is an agricultural film, anautomobile part, a bottle, a container for chemicals, a drum, a fiber orfabric, a food packaging film or container, a food service article, afuel tank, a geomembrane, a household container, a liner, a moldedproduct, a medical device or material, an outdoor storage product,outdoor play equipment, a pipe, a sheet or tape, a toy, or a trafficbarrier.

Aspect 34. The article defined in aspect 32 or 33, wherein the articlehas less than 10 (or less than 5, or less than 2) protrusions or severesurface defects.

Aspect 35. A catalyst composition comprising: catalyst component Icomprising any unbridged metallocene compound disclosed herein, catalystcomponent II comprising any bridged metallocene compound disclosedherein, any activator disclosed herein, and optionally, any co-catalystdisclosed herein.

Aspect 36. The composition defined in aspect 35, wherein catalystcomponent II comprises a bridged zirconium or hafnium based metallocenecompound.

Aspect 37. The composition defined in aspect 35, wherein catalystcomponent II comprises a bridged zirconium or hafnium based metallocenecompound with an alkenyl substituent.

Aspect 38. The composition defined in aspect 35, wherein catalystcomponent II comprises a bridged zirconium or hafnium based metallocenecompound with an alkenyl substituent and a fluorenyl group.

Aspect 39. The composition defined in aspect 35, wherein catalystcomponent II comprises a bridged zirconium or hafnium based metallocenecompound with a cyclopentadienyl group and a fluorenyl group, and withan alkenyl substituent on the bridging group and/or on thecyclopentadienyl group.

Aspect 40. The composition defined in aspect 35, wherein catalystcomponent II comprises a bridged metallocene compound having an arylgroup substituent on the bridging group.

Aspect 41. The composition defined in any one of aspects 35-40, whereincatalyst component I comprises an unbridged zirconium or hafnium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group.

Aspect 42. The composition defined in any one of aspects 35-40, whereincatalyst component I comprises an unbridged zirconium or hafnium basedmetallocene compound containing two cyclopentadienyl groups.

Aspect 43. The composition defined in any one of aspects 35-40, whereincatalyst component I comprises an unbridged zirconium or hafnium basedmetallocene compound containing two indenyl groups.

Aspect 44. The composition defined in any one of aspects 35-40, whereincatalyst component I comprises an unbridged zirconium or hafnium basedmetallocene compound containing a cyclopentadienyl and an indenyl group.

Aspect 45. The composition defined in any one of aspects 35-44, whereinthe activator comprises an activator-support, an aluminoxane compound,an organoboron or organoborate compound, an ionizing ionic compound, orany combination thereof.

Aspect 46. The composition defined in any one of aspects 35-44, whereinthe activator comprises an aluminoxane compound.

Aspect 47. The composition defined in any one of aspects 35-44, whereinthe activator comprises an organoboron or organoborate compound.

Aspect 48. The composition defined in any one of aspects 35-44, whereinthe activator comprises an ionizing ionic compound.

Aspect 49. The composition defined in any one of aspects 35-44, whereinthe activator comprises an activator-support, the activator-supportcomprising any solid oxide treated with any electron-withdrawing aniondisclosed herein.

Aspect 50. The composition defined in any one of aspects 35-44, whereinthe activator comprises fluorided alumina, chlorided alumina, bromidedalumina, sulfated alumina, fluorided silica-alumina, chlorided silicaalumina bromided sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, fluorided-chloridedsilica-coated alumina, fluorided silica-coated alumina, sulfatedsilica-coated alumina, phosphated silica-coated alumina, or anycombination thereof.

Aspect 51. The composition defined in any one of aspects 35-44, whereinthe activator comprises a fluorided solid oxide and/or a sulfated solidoxide.

Aspect 52. The composition defined in any one of aspects 35-51, whereinthe catalyst composition comprises a co-catalyst, e.g., any co-catalystdisclosed herein.

Aspect 53. The composition defined in any one of aspects 35-52, whereinthe co-catalyst comprises any organoaluminum compound disclosed herein.

Aspect 54. The composition defined in aspect 53, wherein theorganoaluminum compound comprises trimethylaluminum, triethylaluminum,triisobutylaluminum, or a combination thereof.

Aspect 55. The composition defined in any one of aspects 49-54, whereinthe catalyst composition comprises catalyst component I, catalystcomponent II, a solid oxide treated with an electron-withdrawing anion,and an organoaluminum compound.

Aspect 56. The composition defined in any one of aspects 49-55, whereinthe catalyst composition is substantially free of aluminoxane compounds,organoboron or organoborate compounds, ionizing ionic compounds, orcombinations thereof.

Aspect 57. The composition defined in any one of aspects 35-56, whereina weight ratio of catalyst component I to catalyst component II in thecatalyst composition is in any range disclosed herein, e.g., from about10:1 to about 1:10, from about 5:1 to about 1:5, from about 2:1 to about1:2, etc.

Aspect 58. The composition defined in any one of aspects 35-57, whereinthe catalyst composition is produced by a process comprising contacting,in any order, catalyst component I, catalyst component II, and theactivator, or contacting, in any order, catalyst component I, catalystcomponent II, the activator, and the co-catalyst.

Aspect 59. The composition defined in any one of aspects 35-58, whereina catalyst activity of the catalyst composition is in any rangedisclosed herein, e.g., from about 150 to about 10,000, from about 500to about 7,500, from about 1,000 to about 5,000 grams, etc., of ethylenepolymer per gram of activator-support per hour, under slurrypolymerization conditions, with a triisobutylaluminum co-catalyst, usingisobutane as a diluent, and with a polymerization temperature of 90° C.and a reactor pressure of 390 psig.

Aspect 60. An olefin polymerization process, the process comprisingcontacting the catalyst composition defined in any one of aspects 35-59with an olefin monomer and an optional olefin comonomer in apolymerization reactor system under polymerization conditions to producean olefin polymer.

Aspect 61. The process defined in aspect 60, wherein the olefin monomercomprises any olefin monomer disclosed herein, e.g., any C₂-C₂₀ olefin.

Aspect 62. The process defined in aspect 60 or 61, wherein the olefinmonomer and the optional olefin comonomer independently comprise aC₂-C₂₀ alpha-olefin.

Aspect 63. The process defined in any one of aspects 60-62, wherein theolefin monomer comprises ethylene.

Aspect 64. The process defined in any one of aspects 60-63, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising a C₃-C₁₀ alpha-olefin.

Aspect 65. The process defined in any one of aspects 60-64, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.

Aspect 66. The process defined in any one of aspects 60-65, wherein thepolymerization reactor system comprises a batch reactor, a slurryreactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Aspect 67. The process defined in any one of aspects 60-66, wherein thepolymerization reactor system comprises a slurry reactor, a gas-phasereactor, a solution reactor, or a combination thereof.

Aspect 68. The process defined in any one of aspects 60-67, wherein thepolymerization reactor system comprises a loop slurry reactor.

Aspect 69. The process defined in any one of aspects 60-68, wherein thepolymerization reactor system comprises a single reactor.

Aspect 70. The process defined in any one of aspects 60-68, wherein thepolymerization reactor system comprises 2 reactors.

Aspect 71. The process defined in any one of aspects 60-68, wherein thepolymerization reactor system comprises more than 2 reactors.

Aspect 72. The process defined in any one of aspects 60-71, wherein theolefin polymer comprises any olefin polymer disclosed herein.

Aspect 73. The process defined in any one of aspects 60-72, wherein theolefin polymer comprises an ethylene homopolymer, an ethylene/1-butenecopolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octenecopolymer.

Aspect 74. The process defined in any one of aspects 60-73, wherein theolefin polymer comprises an ethylene/1-hexene copolymer.

Aspect 75. The process defined in any one of aspects 60-74, wherein thepolymerization conditions comprise a polymerization reaction temperaturein a range from about 60° C. to about 120° C. and a reaction pressure ina range from about 200 to about 1000 psig (about 1.4 to about 6.9 MPa).

Aspect 76. The process defined in any one of aspects 60-75, wherein thepolymerization conditions are substantially constant, e.g., for aparticular polymer grade.

Aspect 77. The process defined in any one of aspects 60-76, wherein nohydrogen is added to the polymerization reactor system.

Aspect 78. The process defined in any one of aspects 60-76, whereinhydrogen is added to the polymerization reactor system.

Aspect 79. The process defined in any one of aspects 60-78, wherein theolefin polymer produced is defined in any one of aspects 1-31.

Aspect 80. An olefin polymer produced by the olefin polymerizationprocess defined in any one of aspects 60-78.

Aspect 81. An ethylene polymer defined in any one of aspects 1-31produced by the process defined in any one of aspects 60-78.

Aspect 82. An article (e.g., a blow molded article) comprising thepolymer defined in aspect 80 or 81.

1. An ethylene polymer having: a density in a range from about 0.952 toabout 0.965 g/cm³; a high load melt index (HLMI) in a range from about 5to about 25 g/10 min; a weight-average molecular weight (Mw) in a rangefrom about 275,000 to about 450,000 g/mol; a number-average molecularweight (Mn) in a range from about 15,000 to about 40,000 g/mol; a HLMIin a range from about 1400 to about 4000 Pa-sec; and a tan δ at 0.1sec⁻¹ in a range from about 0.65 to about 0.98 degrees.
 2. The polymerof claim 1, wherein the ethylene polymer has an environmental stresscrack resistance (ESCR) of at least 500 hours.
 3. The polymer of claim1, wherein the ethylene polymer has a ratio of Mw/Mn in a range fromabout 8 to about
 20. 4. A blow molded article comprising the ethylenepolymer of claim
 1. 5. The polymer of claim 1, wherein the ethylenepolymer has: a CY-a parameter in a range from about 0.18 to about 0.36;and a viscosity at 100 sec⁻¹ in a range from about 1600 to about 2800Pa-sec.
 6. The polymer of claim 1, wherein the ethylene polymer has:less than about 0.008 long chain branches per 1000 total carbon atoms;and a reverse comonomer distribution.
 7. The polymer of claim 1, whereinthe ethylene polymer contains, independently, less than 0.08 ppm byweight of chromium and titanium.
 8. The polymer of claim 1, wherein: thedensity is in a range from about 0.952 to about 0.96 g/cm³; the HLMI isin a range from about 7 to about 15 g/10 min; the Mw is in a range fromabout 300,000 to about 400,000 g/mol; the Mn is in a range from about17,000 to about 40,000 g/mol; the η @ HLMI is in a range from about 1500to about 4000 Pa-sec; and the tan δ at 0.1 sec⁻¹ is in a range fromabout 0.7 to about 0.97 degrees.
 9. The polymer of claim 8, wherein theethylene polymer comprises an ethylene/butene copolymer, anethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer. 10.An article comprising the ethylene polymer of claim
 9. 11. An ethylenepolymer having: a density in a range from about 0.952 to about 0.965g/cm³; a HLMI in a range from about 5 to about 25 g/10 min; a Mw in arange from about 275,000 to about 450,000 g/mol; a Mn in a range fromabout 15,000 to about 28,000 g/mol; and a η @ HLMI in a range from about1400 to about 4000 Pa-sec.
 12. A blow molded article comprising theethylene polymer of claim
 11. 13. The polymer of claim 11, wherein theethylene polymer has: a CY-a parameter in a range from about 0.18 toabout 0.36; and a viscosity at 100 sec⁻¹ in a range from about 1500 toabout 3000 Pa-sec.
 14. The polymer of claim 11, wherein the ethylenepolymer has an ESCR of at least 1000 hours.
 15. The polymer of claim 11,wherein the ethylene polymer has: an IVc in a range from about 2.9 toabout 3.7 dL/g; and a ratio of η @ 0.1/η @ 100 from about 85 to about130.
 16. The polymer of claim 15, wherein: the density is in a rangefrom about 0.952 to about 0.96 g/cm³: the HLMI is in a range from about7 to about 15 g/10 min; the Mw is in a range from about 300,000 to about400,000 g/mol; the Mn is in a range from about 17,000 to about 27,000g/mol; and the η @ HLMI is in a range from about 1500 to about 4000Pa-sec.
 17. An article comprising the ethylene polymer of claim
 16. 18.The article of claim 17, wherein the ethylene polymer comprises anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or anethylene/1-octene copolymer.
 19. A polymerization process, the processcomprising contacting a catalyst composition with ethylene and anα-olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an ethylene polymer, wherein theethylene polymer has: a density in a range from about 0.952 to about0.965 g/cm³; a HLMI in a range from about 5 to about 25 g/10 min; a Mwin a range from about 275,000 to about 450,000 g/mol; a Mn in a rangefrom about 15,000 to about 40,000 g/mol; a η @ HLMI in a range fromabout 1400 to about 4000 Pa-sec; and a tan δ at 0.1 sec⁻¹ in a rangefrom about 0.65 to about 0.98 degrees; and the catalyst compositioncomprises: an unbridged metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group; a bridged metallocene compound with a cyclopentadienylgroup and fluorenyl group, and an alkenyl substituent on thecyclopentadienyl group and/or on the bridging group; anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion; and an organoaluminum compound.
 20. Theprocess of claim 19, wherein: the activator-support comprises fluoridedsolid oxide and/or a sulfated solid oxide; and the polymerizationreactor system comprises a slurry reactor, gas-phase reactor, solutionreactor, or a combination thereof.